[Diagnosis and differential diagnosis of granulosa cell tumor]

Clinically and morphologically, two types of granulosa cell tumor can be distinguished, the more frequent adult type and the juvenile type. In the adult type, different growth patterns can be observed: microfollicular (most frequent, characterized by Call-Exner bodies), macrofollicular, trabecular, insular, solid-tubular, gyriform and diffuse (sarcomatoid). The juvenile type is characterized by solid and follicular structures. The neoplastic granulosa cells in the adult type have limited cytoplasm and haphazardly arranged angular, pale, mostly grooved nuclei. In the juvenile type, the cells have ample eosinophilic cytoplasm and polymorphic, sometimes bizarre nuclei, which are usually non-grooved. The number of mitoses in the adult type usually does not exceed 2/10 HPF, whereas it is considerably higher in the juvenile type, including atypical mitoses. A common feature in both types of tumor is the expression of inhibin-alpha, calretinin and CD 99. Epithelial membrane antigen is negative. Molecular genetics has demonstrated loss of heterozygosity at 19p13.3 in 52% of the cases. Besides chromosomal aberrations, there are a large number of cytogenetic anomalies. The most important prognostic factor in both types of tumor is tumor stage. Whereas recurrences in the adult type can develop even after decades, in the juvenile type they usually occur during the first 3 years after diagnosis.